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<table width="100%" summary="page for sitka"><tr><td>sitka</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Sitka spruce growth data.</h2>

<h3>Description</h3>

<p>Tree growth data under enhanced ozone and control conditions.   
</p>


<h3>Usage</h3>

<pre>
data(sitka)
</pre>


<h3>Format</h3>

<p>A data frame with 1027 rows and 5 columns columns:
</p>

<dl>
<dt>id.num</dt><dd><p>identity of the tree: 1...79.</p>
</dd>
<dt>order</dt><dd><p>time order ranking within each tree.</p>
</dd>
<dt>days</dt><dd><p>since 1st January, 1988.</p>
</dd>
<dt>log.size</dt><dd><p>log of tree &lsquo;size&rsquo;.</p>
</dd>
<dt>ozone</dt><dd><p>1 - enhanced ozone treatment; 0 - control.</p>
</dd>
</dl>



<h3>Details</h3>

<p> The data were analysed in Crainiceanu CM, Ruppert D, Wand MP (2005) using WinBUGS, and in Wood (2016) using auto-generated JAGS code. 
</p>


<h3>Source</h3>

<p>The <code>SemiPar</code> package, from:
</p>
<p>Diggle, P.J, Heagery, P., Liang, K.-Y. and Zeger, S.L. (2002) Analysis of Longitudinal Data (2nd ed.) OUP.
</p>


<h3>References</h3>

<p>Wood SN (2016) &quot;Just Another Gibbs Additive Modeller: Interfacing JAGS and mgcv&quot; Journal of Statistical Software 75
</p>
<p>Crainiceanu C.M., Ruppert D. and Wand M.P. (2005). &quot;Bayesian Analysis for Penalized Spline Regression Using WinBUGS.&quot; Journal of Statistical Software, 14(14).
</p>


<h3>Examples</h3>

<pre>
  require(gamair); require(lattice)
  data(sitka)
  xyplot(log.size~days|as.factor(ozone),data=sitka,type="l",groups=id.num)

</pre>


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